Extended-Release Oxalic Acid Bee Treatment Using Glycerol and Swedish Sponges

Varroa mites are notorious pests that pose a significant threat to honeybee colonies worldwide. Over the years, beekeepers have experimented with various treatments to control these mites without harming the bees or contaminating honey. One method we've found particularly effective is using oxalic acid combined with glycerol and Swedish sponges for an extended-release treatment. In this blog post, we'll share our step-by-step process and our positive experiences with this approach.

Why Oxalic Acid and Glycerol?

Oxalic acid is a natural acaricide that's effective against Varroa mites. When mixed with glycerol, it creates a slow-release mechanism, allowing the oxalic acid to act over an extended period. This method reduces the need for frequent applications and minimizes stress on the bee colony.

Materials You'll Need

Oxalic Acid Dihydrate: A naturally occurring organic compound.
Glycerol: A food-grade, viscous liquid that acts as a carrier.
Swedish Sponges: Also known as cellulose sponges; used as an extender.
Protective Gear: Gloves, goggles, and a mask for safety.
Heat Source: A stove or hot plate to warm the glycerol.
Mixing Container: Heat-resistant and suitable for mixing chemicals.
Measuring Scale: For accurate measurements.

Step-by-Step Guide Oxalic Acid treatment

1. Safety First

Before you begin, put on your protective gear. Oxalic acid can be harmful if it comes into contact with your skin or if fumes are inhaled.

2. Prepare the Oxalic Acid and Glycerol Solution

Measure Ingredients: Use a 1:1 ratio by weight. For example, if you have 100 grams of glycerol, you'll need 100 grams of oxalic acid dihydrate.
Heat the Glycerol: Pour the glycerol into your mixing container and gently heat it. It should be warm but not boiling. You should heat the glycerol to approximately 50–65°C (122–145°F).
Add Oxalic Acid: Gradually add the oxalic acid to the heated glycerol while stirring continuously.
Stir Until Clear: Continue stirring until the mixture becomes clear, indicating that the oxalic acid has fully dissolved.

3. Prepare the Swedish Sponges

Cut the Sponges: Take each Swedish sponge and cut it into four equal strips.
Soak the Strips: Place the sponge strips in a shallow tray and pour the oxalic acid and glycerol solution over them. Ensure they're fully saturated.
Let Them Rest: Allow the soaked strips to rest overnight. This ensures the solution is evenly distributed and fully absorbed.

Applying the Treatment to the Hives

For Productive Hives

Number of Strips: Use four sponge strips per hive.
Placement: Insert the strips between the two brood boxes. Position them so that bees can easily come into contact with the strips as they move between boxes.

For Nucleus Hives (Nucs)

Number of Strips: Use two sponge strips per nuc.
Placement: Place the strips directly above the frames where the bees are most active.

Timing is Everything

We apply this treatment after the honey flow is over. This timing ensures that there's no risk of honey contamination (some beekeepers use this also in a production season) and targets the Varroa mites when they're most vulnerable.

Our Positive Experience

Since implementing this method, we've noticed a significant reduction in Varroa mite infestations. Here's what we've observed:

Effective Mite Control: Autumn Varroa checks show that almost all colonies are clear of mites.
Healthy Bees: The colonies remain strong and productive, with no adverse effects observed from the treatment.
Ease of Use: The preparation and application process is straightforward and doesn't require specialized equipment.
Cost-Effective: The materials are affordable, making it a sustainable option for beekeepers of all sizes.

Benefits of Using Swedish Sponges

Swedish sponges serve as an excellent medium for the extended-release of oxalic acid:

Highly Absorbent: They hold a substantial amount of the solution.
Biodegradable: Made from natural cellulose, they're environmentally friendly.
Bee-Friendly: Bees readily come into contact with them without any signs of stress or avoidance.

Tips and Precautions

Regulatory Compliance: Always check local regulations regarding the use of oxalic acid in beekeeping.
Avoid Honey Contamination: Ensure treatments are done when supers are not on the hives.
Monitor Bee Behavior: After application, observe the bees for any unusual behavior.
Dispose of Used Strips Properly: After the treatment period, remove and dispose of the strips according to safety guidelines.

Oxalic Acid extended release treatment on nuces

Conclusion

Controlling Varroa mites is crucial for the health and longevity of bee colonies. Our experience with using oxalic acid and glycerol-soaked Swedish sponges has been overwhelmingly positive. It's an effective, economical, and relatively simple method that has kept our hives thriving.

Have you tried this method or have other Varroa mite control tips? Share your experiences in the comments below! Together, we can support healthy bee populations and sustainable beekeeping practices.